Control method of an automatic inside-diameter measuring apparatus and an automatic measuring apparatus

ABSTRACT

There is provided an inside-diameter measuring unit capable of automating inside-diameter measurement and a control method for automatic inside-diameter measurement. An inside-diameter measuring part is supported by a support frame part via a floating joint part. The floating joint part includes a rotation-allowing mechanism part and a translation-allowing mechanism part. A measuring head part of the inside-diameter measuring part is inserted into a hole by a robot arm part. The inside-diameter measuring part adjusts its position and posture autonomously by the reaction force when a contact point pushes against the inner wall of the hole to align the axis of the inside-diameter measuring part with the axis of the hole. An electric inside-diameter measuring unit can automatically measure the inside diameter of a hole.

INCORPORATION BY REFERENCE

This application is based upon and claims the benefit of priority fromJP patent application No. 2022-049144, filed on Mar. 24, 2022 (DAS codeA63E), the disclosure of which is incorporated herein in its entirety byreference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to an inside-diameter measuring unit, afloating joint mechanism part, and a measuring unit.

2. Description of Related Art

Measuring devices for measuring the inside diameter of holes areinside-diameter measuring devices, such as hole tests, cylinder gauges,and Borematic (registered trademark) (see, for example, PatentLiterature 1: JP 2010-19783 A). However, when using such aninside-diameter measuring device, manual measurement is inevitablyrequired, because its contact point must be moved forward and backwardor centering is performed to some extent while the inside-diametermeasuring device is inserted in a hole. Therefore, it takes a lot ofmanpower and time to check the machining accuracy of a hole with such aninside-diameter measuring device.

As an alternative to manual measurement, an air micrometer is aninside-diameter measuring apparatus that automates inside-diametermeasurement at production sites (see, for example, Patent Literature 2:JP H8-14871). The air micrometer, which is simply inserted into a holeand blows air out, is a suitable measuring apparatus for automatinginside-diameter measurement among the current options.

-   Patent Literature 1: JP 2010-19783 A-   Patent Literature 2: JP H8-14871

SUMMARY OF THE INVENTION

However, air micrometers also have the following disadvantages.

First, air micrometers are very expensive because of their structure. Inaddition, an air compressor needs to be prepared and maintained. Interms of measurement capability, the repeatability of air micrometers islimited due to their structure, and their measurement range is extremelyshort (a few hundred micrometers).

A common problem with manual measurement using manual measuring deviceshas been the demand to automate measurement as inexpensively aspossible.

There is a need for a measuring unit that is inexpensive, easy to use,and can automate measurement and a control method for automaticmeasurement.

For example, there is a need for an inside-diameter measuring unit thatis inexpensive, easy to use, and can automatically measure holediameters and a control method for automatic inside-diametermeasurement.

An inside-diameter measuring unit according to an exemplary embodimentof the present invention includes:

-   -   an inside-diameter measuring part including a contact point        configured to move forward and backward in a direction        perpendicular to a cylinder axis of a cylinder case part, the        inside-diameter measuring part configured to bring the contact        point into contact with an inner wall of a hole to be measured        to measure an inside diameter of the hole while the        inside-diameter measuring part is inserted in the hole;    -   a support frame part configured to support the inside-diameter        measuring part; and    -   a floating joint part interposed between the support frame part        and the inside-diameter measuring part to allow relative        translation and rotation of the inside-diameter measuring part        with respect to the support frame part, wherein    -   the floating joint part includes:        -   a rotation-allowing mechanism part configured to allow the            rotation of the inside-diameter measuring part with respect            to the support frame part; and        -   a translation-allowing mechanism part configured to allow            translational displacement of the inside-diameter measuring            part with respect to the support frame part    -   the rotation-allowing mechanism part includes a flexible body        configured to allow deformation in a direction in which the        inside-diameter measuring part is inclined    -   the translation-allowing mechanism part includes a translation        body configured to allow translation of the inside-diameter        measuring part in a direction intersecting the cylinder axis of        the cylinder case part    -   the flexible body has one end coupled to the inside-diameter        measuring part    -   the flexible body has the other end coupled to the translation        body, and    -   the translation body is supported in such a manner as to be        translatable with respect to the support frame part.

In an exemplary embodiment of the present invention, it is preferablethat

-   -   the support frame part includes a support base part    -   the support base part includes a first insertion hole through        which the inside-diameter measuring part is inserted    -   the translation body includes a second insertion hole through        which the inside-diameter measuring part is inserted    -   the inside-diameter measuring part is supported while being        inserted in the first insertion hole and the second insertion        holes, and    -   the floating joint part includes a bearing provided around the        first insertion hole and the second insertion hole between the        translation body and the support base part to allow translation        of the translation body with respect to the support base part.

In an exemplary embodiment of the present invention, it is preferablethat

-   -   the first insertion hole has a larger diameter than a diameter        of the second insertion hole    -   the diameter of the first insertion hole has a size allowing the        translation of the inside-diameter measuring part, and    -   the diameter of the second insertion hole has a size allowing        the inclination of the inside-diameter measuring part.

In an exemplary embodiment of the present invention, it is preferablethat the flexible body is an elastic body provided to surround theinside-diameter measuring part between the inside-diameter measuringpart and the translation body.

In an exemplary embodiment of the present invention, it is preferablethat the elastic body is a spring provided to surround theinside-diameter measuring part.

In an exemplary embodiment of the present invention, it is preferablethat

-   -   the translation body is disposed above the support base part    -   the flexible body has a lower end coupled to the translation        body as the other end, and    -   the flexible body has an upper end coupled to the        inside-diameter measuring part as the one end.

In an exemplary embodiment of the present invention, it is preferablethat a position at which the one end of the flexible body is coupled tothe inside-diameter measuring part corresponds to a center of gravity ofthe inside-diameter measuring part.

In an exemplary embodiment of the present invention, it is preferablethat the inside-diameter measuring unit further includes an electricdrive unit configured to move the contact point forward and backward.

In an exemplary embodiment of the present invention, it is preferablethat

-   -   the inside-diameter measuring unit further includes a        restriction means for clamping the inside-diameter measuring        part from a direction intersecting the cylinder axis, wherein    -   the restriction means is configured to clamp and hold the        inside-diameter measuring part when the inside-diameter        measuring part is not inserted in the hole to be measure, and to        release the inside-diameter measuring part when the        inside-diameter measuring part is inserted in the hole to be        measured.

In an exemplary embodiment of the present invention, it is preferablethat the inside-diameter measuring part is supported by the supportframe part via the floating joint part when the cylinder axis isoriented in a vertical direction as a reference position.

In an exemplary embodiment of the present invention, it is preferablethat the support frame part couples the inside-diameter measuring partto a moving means for moving the inside-diameter measuring part.

A floating joint mechanism part according to an exemplary embodiment ofthe present invention is a floating joint mechanism part interposedbetween an object to be supported and a support frame part configured tosupport the object to be supported, the floating joint mechanism partconfigured to allow relative translation and rotation of the object tobe supported with respect to the support frame part, the floating jointmechanism part includes:

-   -   a rotation-allowing mechanism part configured to allow the        rotation of the object to be supported with respect to the        support frame part; and    -   a translation-allowing mechanism part configured to allow        translational displacement of the object to be supported with        respect to the support frame part, wherein    -   the rotation-allowing mechanism part includes a flexible body        configured to allow deformation in a direction in which the        object to be supported is inclined    -   the translation-allowing mechanism part includes a translation        body configured to allow translation of the object to be        supported    -   the flexible body has one end coupled to the object to be        supported    -   the flexible body has the other end coupled to the translation        body, and    -   the translation body is supported in such a manner as to be        translatable with respect to the support frame part.

A measuring unit according to an exemplary embodiment of the presentinvention includes:

-   -   a measuring part configured to bring a contact point into        contact with an object to be measured to measure a dimension of        the object to be measured;    -   a support frame part configured to support the measuring part;        and    -   a floating joint part interposed between the support frame part        and the measuring part to allow relative translation and        rotation of the measuring part with respect to the support frame        part, wherein    -   the floating joint part includes:        -   a rotation-allowing mechanism part configured to allow the            rotation of the measuring part with respect to the support            frame part; and        -   a translation-allowing mechanism part configured to allow            translational displacement of the measuring part with            respect to the support frame part    -   the rotation-allowing mechanism part includes a flexible body        configured to allow deformation in a direction in which the        measuring part is inclined    -   the translation-allowing mechanism part includes a translation        body configured to allow translation of the measuring part    -   the flexible body has one end coupled to the measuring part    -   the flexible body has the other end coupled to the translation        body, and    -   the translation body is supported in such a manner as to be        translatable with respect to the support frame part.

An inside-diameter measuring unit according to an exemplary embodimentof the present invention includes:

-   -   an inside-diameter measuring part including a contact point        configured to move forward and backward in a direction        perpendicular to a cylinder axis of a cylinder case part, the        inside-diameter measuring part configured to bring the contact        point into contact with an inner wall of a hole to be measured        to measure an inside diameter of the hole while the        inside-diameter measuring part is inserted in the hole;    -   a support frame part configured to support the inside-diameter        measuring part; and    -   a floating joint part interposed between the support frame part        and the inside-diameter measuring part to allow relative        translation and rotation of the inside-diameter measuring part        with respect to the support frame part, wherein    -   the floating joint part includes:        -   a coupling block fixedly coupled to the inside-diameter            measuring part and configured to be translated and rotated            integrally with the inside-diameter measuring part;        -   a rotation-allowing mechanism part configured to allow            rotation of the coupling block with respect to the support            frame part; and        -   a translation-allowing mechanism part configured to allow            translational displacement of the coupling block in a            direction parallel to a plane perpendicular to the cylinder            axis with respect to the support frame part    -   the rotation-allowing mechanism part includes a sphere disposed        between the coupling block and the support frame part, and    -   the translation-allowing mechanism part includes:        -   a guide shaft provided to either one of the coupling block            and the support frame part and extending in the direction            parallel to the plane perpendicular to the cylinder axis;            and        -   a guide hole provided in the other one of the coupling block            and the support frame part to receive the guide shaft and            allow the guide shaft to slide in the direction parallel to            the plane perpendicular to the cylinder axis.

In an exemplary embodiment of the present invention, it is preferablethat

-   -   the guide shaft is one of two guide shafts, and    -   the two guide shafts are provided in mutually orthogonal        directions in the plane perpendicular to the cylinder axis.

In an exemplary embodiment of the present invention, it is preferablethat

-   -   the support frame part includes a support ring part surrounding        the coupling block in the plane perpendicular to the cylinder        axis    -   the support ring part is provided with the two guide shafts, and    -   the coupling block includes a guide hole configured to receive        the two guide shafts and allow translation and rotation of the        coupling block.

In an exemplary embodiment of the present invention, it is preferablethat

-   -   the coupling block is disposed above an upper end of the        inside-diameter measuring part, and    -   the inside-diameter measuring part is supported by the support        frame part while being suspended from the support frame part via        the floating joint part.

In an exemplary embodiment of the present invention, it is preferablethat a position at which the two guide shafts intersect is on anextension of the cylinder axis of the inside-diameter measuring part.

In an exemplary embodiment of the present invention, it is preferablethat the inside-diameter measuring unit further includes an electricdrive unit configured to move the contact point forward and backward.

In an exemplary embodiment of the present invention, it is preferablethat

-   -   the inside-diameter measuring unit further includes a        restriction means for clamping the inside-diameter measuring        part or the coupling block to hold the inside-diameter measuring        part, wherein    -   the restriction means is configured to hold the inside-diameter        measuring part when the inside-diameter measuring part is not        inserted in a hole to be measured, and to release the        inside-diameter measuring part when the inside-diameter        measuring part is inserted in the hole to be measured.

In an exemplary embodiment of the present invention, it is preferablethat the inside-diameter measuring part is supported by the supportframe part via the floating joint part when the cylinder axis isoriented in a vertical direction as a reference position.

In an exemplary embodiment of the present invention, it is preferablethat the support frame part couples the inside-diameter measuring partto a moving means for moving the inside-diameter measuring part.

A floating joint mechanism part according to an exemplary embodiment ofthe present invention is a floating joint mechanism part interposedbetween an object to be supported and a support frame part configured tosupport the object to be supported, the floating joint mechanism partconfigured to allow relative translation and rotation of the object tobe supported with respect to the support frame part, the floating jointmechanism part includes:

-   -   a coupling block fixedly coupled to the object to be supported        and configured to be translated and rotated integrally with the        object to be supported;    -   a rotation-allowing mechanism part configured to allow rotation        of the coupling block with respect to the support frame part;        and    -   a translation-allowing mechanism part configured to allow        translational displacement of the coupling block with respect to        the support frame part    -   the rotation-allowing mechanism part includes a sphere disposed        between the coupling block and the support frame part, and    -   the translation-allowing mechanism part includes:        -   a guide shaft provided to either one of the coupling block            and the support frame part and extending in a direction of            guiding translation; and        -   a guide hole provided in the other one of the coupling block            and the support frame part to receive the guide shaft and            allow the guide shaft to slide.

A measuring unit according to an exemplary embodiment of the presentinvention includes:

-   -   a measuring part configured to bring a contact point into        contact with an object to be measured to measure a dimension of        the object to be measured;    -   a support frame part configured to support the measuring part;        and    -   a floating joint part interposed between the support frame part        and the measuring part to allow relative translation and        rotation of the measuring part with respect to the support frame        part, wherein    -   the floating joint part includes:        -   a coupling block fixedly coupled to the measuring part and            configured to be translated and rotated integrally with the            measuring part;        -   a rotation-allowing mechanism part configured to allow            rotation of the coupling block with respect to the support            frame part; and        -   a translation-allowing mechanism part configured to allow            translational displacement of the coupling block with            respect to the support frame part    -   the rotation-allowing mechanism part includes a sphere disposed        between the coupling block and the support frame part, and    -   the translation-allowing mechanism part includes:        -   a guide shaft provided to either one of the coupling block            and the support frame part and extending in a direction of            guiding translation; and        -   a guide hole provided in the other one of the coupling block            and the support frame part to receive the guide shaft and            allow the guide shaft to slide.

An inside-diameter measuring unit according to an exemplary embodimentof the present invention includes:

-   -   an inside-diameter measuring part including a contact point        configured to move forward and backward in a direction        perpendicular to a cylinder axis of a cylinder case part, the        inside-diameter measuring part configured to bring the contact        point into contact with an inner wall of a hole to be measured        to measure an inside diameter of the hole while the        inside-diameter measuring part is inserted in the hole;    -   a support frame part configured to support the inside-diameter        measuring part; and    -   a floating joint part interposed between the support frame part        and the inside-diameter measuring part to allow relative        translation and rotation of the inside-diameter measuring part        with respect to the support frame part, wherein    -   the floating joint part includes:        -   a first floating coupling body fixedly coupled to the            inside-diameter measuring part and configured to be            translated and rotated integrally with the inside-diameter            measuring part;        -   a second floating coupling body configured to support the            first floating coupling body to allow translation and            rotation of the first floating coupling body; and        -   a third floating coupling body configured to support the            second floating coupling body to allow translation and            rotation of the second floating coupling body, and    -   the third floating coupling body is fixedly attached to the        support frame part.

In an exemplary embodiment of the present invention, it is preferablethat

-   -   the second floating coupling body supports the first floating        coupling body via a first coupling shaft extending in a first        direction parallel to a plane perpendicular to the cylinder        axis, the first coupling shaft configured to allow axially        forward and backward movement and axial rotation, and    -   the third floating coupling body supports the second floating        coupling body via a second coupling shaft extending in a        direction perpendicular to the first direction in the plane        perpendicular to the cylinder axis, the second coupling shaft        configured to allow axially forward and backward movement and        axial rotation.

In an exemplary embodiment of the present invention, it is preferablethat

-   -   the first floating coupling body is ring shaped or cylinder        shaped and provided to surround the inside-diameter measuring        part in the direction perpendicular to the cylinder axis, and    -   the second floating coupling body is ring shaped or cylinder        shaped and provided to surround the first floating coupling body        in the direction perpendicular to the cylinder axis.

In an exemplary embodiment of the present invention, it is preferablethat a position at which a first virtual straight line being a virtualextension of the first coupling shaft and a second virtual straight linebeing a virtual extension of the second coupling shaft intersect issubstantially aligned with a center of gravity of the inside-diametermeasuring part.

In an exemplary embodiment of the present invention, it is preferablethat the inside-diameter measuring unit further includes an electricdrive unit configured to move the contact point forward and backward.

In an exemplary embodiment of the present invention, it is preferablethat

-   -   the inside-diameter measuring unit further includes a        restriction means for clamping the inside-diameter measuring        part from a direction intersecting the cylinder axis, wherein    -   the restriction means is configured to clamp and hold the        inside-diameter measuring part when the inside-diameter        measuring part is not inserted in a hole to be measured, and to        release the inside-diameter measuring part when the        inside-diameter measuring part is inserted in the hole to be        measured.

In an exemplary embodiment of the present invention, it is preferablethat the inside-diameter measuring part is supported by the supportframe part via the floating joint part when the cylinder axis isoriented in a vertical direction as a reference position.

A floating joint mechanism part according to an exemplary embodiment ofthe present invention is a floating joint mechanism part interposedbetween an object to be supported and a support frame part configured tosupport the object to be supported, the floating joint mechanism partconfigured to allow relative translation and rotation of the object tobe supported with respect to the support frame part, the floating jointmechanism part includes:

-   -   a first floating coupling body fixedly coupled to the object to        be supported and configured to be translated and rotated        integrally with the object to be supported;    -   a second floating coupling body configured to support the first        floating coupling body to allow translation and rotation of the        first floating coupling body; and    -   a third floating coupling body configured to support the second        floating coupling body to allow translation and rotation of the        second floating coupling body, wherein    -   the third floating coupling body is fixedly attached to the        support frame part.

A measuring unit according to an exemplary embodiment of the presentinvention includes:

-   -   a measuring part configured to bring a contact point into        contact with an object to be measured to measure a dimension of        the object to be measured;    -   a support frame part configured to support the measuring part;        and    -   a floating joint part interposed between the support frame part        and the measuring part to allow relative translation and        rotation of the measuring part with respect to the support frame        part, wherein    -   the floating joint part includes:        -   a first floating coupling body fixedly coupled to the            measuring part and configured to be translated and rotated            integrally with the measuring part;        -   a second floating coupling body configured to support the            first floating coupling body to allow translation and            rotation of the first floating coupling body; and        -   a third floating coupling body configured to support the            second floating coupling body to allow translation and            rotation of the second floating coupling body, and    -   the third floating coupling body is fixedly attached to the        support frame part.

A control method of an automatic inside-diameter measuring apparatus,the automatic inside-diameter measuring apparatus including:

-   -   an inside-diameter measuring part including a contact point        configured to move forward and backward in a direction        perpendicular to a cylinder axis of a cylinder case part, an        electric drive unit configured to move the contact point forward        and backward, and a displacement detection part configured to        detect displacement of the contact point;    -   a moving means for relatively moving the inside-diameter        measuring part with respect to an object to be measured to        insert and retract the inside-diameter measuring part into and        from a hole to be measured; and    -   a control unit configured to control operation of the        inside-diameter measuring part and the moving means, the control        method includes:    -   a hole insertion step of inserting, by the moving means, the        inside-diameter measuring part into the hole to be measured;    -   a measurement step of bringing the contact point into contact        with an inner wall of the hole to measure an inside diameter of        the hole; and    -   a hole retraction step of retracting the inside-diameter        measuring part from the hole by the moving means.

In an exemplary embodiment of the present invention, it is preferablethat

-   -   the automatic inside-diameter measuring apparatus further        includes:    -   a support frame part configured to support the inside-diameter        measuring part and to couple the inside-diameter measuring part        to the moving means; and    -   a floating joint part interposed between the support frame part        and the inside-diameter measuring part to allow relative        translation and rotation of the inside-diameter measuring part        with respect to the support frame part    -   the hole insertion step including temporarily stopping drive of        the moving means after the inside-diameter measuring part is        inserted by the moving means into the hole to be measured, and    -   the measurement step includes an autonomous adjustment step of        autonomously adjusting, by the inside-diameter measuring part, a        position and posture of the inside-diameter measuring part        itself to align the cylinder axis of the cylinder case part with        an axis of the hole to be measured while the inside-diameter        measuring part is relatively displaced with respect to the        support frame part by a reaction force applied to the        inside-diameter measuring part from the inner wall of the hole        to be measured when the electric drive unit moves the contact        point forward and brings the contact point into contact with the        inner wall of the hole to be measured.

In an exemplary embodiment of the present invention, it is preferablethat

-   -   the automatic inside-diameter measuring apparatus further        includes a restriction means for clamping the inside-diameter        measuring part from a direction intersecting the cylinder axis    -   the restriction means is configured to switch between a holding        state and a release state of the inside-diameter measuring part        by performing a holding step of clamping and restricting the        inside-diameter measuring part and a release step of releasing        the restriction of the inside-diameter measuring part    -   the restriction means maintains the holding state of the        inside-diameter measuring part during the hole insertion step        and the hole retraction step, and    -   the measurement step includes performing, by the restriction        means, the releasing step before the autonomous adjustment step        to release the restriction of the inside-diameter measuring        part.

In an exemplary embodiment of the present invention, it is preferablethat

-   -   the control unit includes a drive control unit configured to        control the electric drive unit    -   the measurement step includes:        -   a first forward movement step of moving, by the drive            control unit, the contact point forward until the contact            point is brought into first contact with the inner wall of            the hole to be measured;        -   a backward movement step of moving, by the drive control            unit, the contact point backward slightly in an opposite            direction after the first forward movement step; and        -   a second forward movement step of moving, by the drive            control unit, the contact point forward again after the            backward movement step to perform the autonomous adjustment            step.

In an exemplary embodiment of the present invention, it is preferablethat the releasing step is performed before the first forward movementstep.

In an exemplary embodiment of the present invention, it is preferablethat the releasing step is performed after the first forward movementstep.

In an exemplary embodiment of the present invention, it is preferablethat

-   -   a constant pressure mechanism configured to regulate an upper        limit of the reaction force applied to the contact point from        the inner wall of the hole to be measured is provided in a force        transmission path from the electric drive unit to the contact        point, and    -   the drive control unit terminates the second forward movement        step when the constant pressure mechanism is activated.

In an exemplary embodiment of the present invention, it is preferablethat

-   -   the automatic inside-diameter measuring apparatus further        includes a collision detection part configured to detect that        the inside-diameter measuring part has collided with an object,        and    -   the hole insertion step is stopped when the collision detection        part detects a collision.

A control method of an automatic measuring apparatus, the automaticmeasuring apparatus including:

-   -   a measuring part including a contact point provided to move        forward and backward with respect to a fixed element, an        electric drive unit configured to move the contact point forward        and backward, and a displacement detection part configured to        detect displacement of the contact point;    -   a moving means for relatively moving the measuring part with        respect to an object to be measured to bring the measuring part        closer to or in contact with the object to be measured; and    -   a control unit configured to control operation of the measuring        part and the moving means, the control method includes:    -   an approaching step of bringing, by the moving means, the        measuring part closer to the object to be measured;    -   a measurement step of bringing the contact point into contact        with the object to be measured to measure a dimension of the        object to be measured; and    -   a retraction step of retracting, by the moving means, the        measuring part from the object to be measured.

In an exemplary embodiment of the present invention, it is preferablethat

-   -   the automatic measuring apparatus further includes:    -   a support frame part configured to support the measuring part        and to couple the measuring part to the moving means; and    -   a floating joint part interposed between the support frame part        and the measuring part to allow relative translation and        rotation of the measuring part with respect to the support frame        part    -   the approaching step including temporarily stopping drive of the        moving means after the measuring part is brought, by the moving        means, closer to or into contact with the object to be measured,        and    -   the measurement step includes an autonomous adjustment step of        autonomously adjusting, by the measuring part, a position and        posture of the measuring part itself while the measuring part is        relatively displaced with respect to the support frame part by a        reaction force applied to the measuring part from object to be        measured when the electric drive unit moves the contact point        forward and brings the contact point into contact with object to        be measured.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an external view of an entire automatic inside-diametermeasuring apparatus;

FIG. 2 is an external perspective view of an electric inside-diametermeasuring unit when viewed from a slightly front side;

FIG. 3 is an external perspective view of the side of the electricinside-diameter measuring unit when viewed from a slightly rear side;

FIG. 4 is a front view of the electric inside-diameter measuring unit;

FIG. 5 is a cross-sectional view for showing the internal structure ofan electric inside-diameter measuring device;

FIG. 6 is an exploded view of a floating joint part according to anfirst exemplary embodiment;

FIG. 7 is a cross-sectional view of the floating joint part according tothe first exemplary embodiment;

FIG. 8 is a view for explaining a function of the floating joint partfor adjusting the position and posture of the electric inside-diametermeasuring device according to the first exemplary embodiment;

FIG. 9 is a view for explaining the function of the floating joint partfor adjusting the position and posture of the electric inside-diametermeasuring device according to the first exemplary embodiment;

FIG. 10 is a view for explaining the function of the floating joint partfor adjusting the position and posture of the electric inside-diametermeasuring device according to the first exemplary embodiment;

FIG. 11 is a view for explaining the function of the floating joint partfor adjusting the position and posture of the electric inside-diametermeasuring device according to the first exemplary embodiment;

FIG. 12 is a view for explaining the function of the floating joint partfor adjusting the position and posture of the electric inside-diametermeasuring device according to the first exemplary embodiment;

FIG. 13 is an exploded view of a collision detection part;

FIG. 14 is a perspective view of the collision detection part whenviewed from a slightly rear side;

FIG. 15 is a functional block diagram of a control unit;

FIG. 16 is a flowchart of the overall operation of automaticinside-diameter measurement;

FIG. 17 is a flowchart showing an operating procedure of a holeinsertion step (ST100);

FIG. 18 is a flowchart showing an operating procedure of a measurementstep (ST200);

FIG. 19 is a flowchart showing an operating procedure of a holeretraction step (ST300);

FIG. 20 is a flowchart showing an operating procedure of a measurementstep according to a second exemplary embodiment;

FIG. 21 is a flowchart showing an operating procedure of a measurementstep according to a third exemplary embodiment;

FIG. 22 is a front view of an electric inside-diameter measuring unitaccording to a fourth exemplary embodiment;

FIG. 23 is a top view (plan view) of a floating joint part according tothe fourth exemplary embodiment;

FIG. 24 is a cross-sectional view taken along the XXIV-XXIV line in FIG.23 ;

FIG. 25 is a perspective view when a coupling block according to thefourth exemplary embodiment is rotated and displaced with respect to asupport frame part (support base part);

FIG. 26 is a cross-sectional view when the coupling block according tothe fourth exemplary embodiment is rotated and displaced with respect tothe support frame part (support base part);

FIG. 27 is a top view (plan view) when the coupling block according tothe fourth exemplary embodiment is horizontally translated;

FIG. 28 is a perspective view of an electric inside-diameter measuringunit according to a fifth exemplary embodiment;

FIG. 29 is a top view (plan view) of the electric inside-diametermeasuring unit according to the fifth exemplary embodiment;

FIG. 30 is a view when a first floating coupling cup according to thefifth exemplary embodiment is rotated around an X-axis;

FIG. 31 is a view when the first floating coupling cup according to thefifth exemplary embodiment is translated in a horizontal plane;

FIG. 32 is an exterior side view according to a sixth exemplaryembodiment; and

FIG. 33 is an enlarged cross-sectional view of a floating joint partaccording to the sixth exemplary embodiment.

DETAILED DESCRIPTION

Exemplary embodiments of the present invention are illustrated anddescribed with reference to the reference signs assigned to the elementsin the drawings.

First Exemplary Embodiment

In the following, a first exemplary embodiment of the present inventionis described.

The present exemplary embodiment describes an automatic inside-diametermeasuring apparatus 100 that automates the measurement of the insidediameter (hole diameter) of a hole to be measured.

(Automatic Inside-Diameter Measuring Apparatus)

FIG. 1 is an external view of the entire automatic inside-diametermeasuring apparatus 100.

The automatic inside-diameter measuring apparatus 100 includes ameasuring-apparatus main body 110 and a control unit 140 that controlsthe overall operation.

(Measuring-Apparatus Main Body 110)

The measuring-apparatus main body 110 includes an electricinside-diameter measuring unit 120 that measures the hole diameter of anobject to be measured, and a multi-joint robot arm part (robot arm part)130 as a moving means for moving the electric inside-diameter measuringunit 120.

(Electric Inside-Diameter Measuring Unit 120)

The electric inside-diameter measuring unit 120 is attached to and heldby a hand part 131, which is the tip of the robot arm part 130. Theelectric inside-diameter measuring unit 120 is inserted into a hole thatis an object to be measured to measure the inside diameter. In addition,the electric inside-diameter measuring unit 120 has a function toautonomously adjust its own position and posture to accurately measure ahole that is an object to be measured.

The configuration of the electric inside-diameter measuring unit 120 isdescribed.

FIG. 2 is an external perspective view of the electric inside-diametermeasuring unit 120 when viewed from a slightly front side.

FIG. 3 is an external perspective view of the side of the electricinside-diameter measuring unit 120 when viewed from a slightly rearside.

FIG. 4 is a front view of the electric inside-diameter measuring unit120.

The electric inside-diameter measuring unit 120 includes an electricinside-diameter measuring device (object to be supported) 200, a supportframe part 300, a floating joint part (floating joint mechanism part)400, a restriction means 500, a collision detection part 600, and aforce sensor part 132.

(Electric Inside-Diameter Measuring Device 200)

The electric inside-diameter measuring device 200 is an electric versionof the rod feed of an existing manual inside-diameter measuring device(for example, Hole test).

FIG. 5 is a cross-sectional view for showing the internal structure ofthe electric inside-diameter measuring device 200.

The electric inside-diameter measuring device 200 includes a cylindercase part (fixed element) 210, a rod 230, a thimble part 240, a contactpoint (movable element) 250, a displacement detection part 260, an outercase part 270, a display unit 273, and an electric drive unit 280.

The cylinder case part 210 is a case having a cylindrical shape as awhole.

The rod 230 moves axially forward and backward inside the cylinder casepart 210.

The cylinder case part 210 includes an upper cylinder case part 211constituting an upper part, a middle cylinder case part 213 constitutinga middle part, a lower cylinder case part 214 constituting a lower part,and a head cylinder part 215 constituting a measuring head part 220.

The middle cylinder case part 213 is attached to the lower end of theupper cylinder case part 211, the lower cylinder case part 214 isattached to the lower end of the middle cylinder case part 213, and thehead cylinder part 215 is attached to the lower end of the lowercylinder case part 214.

The rod 230 is a long rod-shaped body as a whole. The rod 230 includesan upper rod 231 and a lower rod 233. The upper rod 231 is a spindle andhas a feed screw (male thread) 232 on the outer surface of its base end(upper end side). The upper cylinder case part 211 has a female thread212, and the feed screw 232 is screwed with the female thread 212.

The thimble part 240 is provided at the base end (upper end side) of theupper rod 231.

The thimble part 240 includes a thimble sleeve 241, a ratchet sleeve242, and a coil spring 243.

The thimble sleeve 241 is fitted externally to the base end of the upperrod 231 (rod 230) by a tapered surface fit and is adhered to the baseend of the upper rod 231 (rod 230).

The ratchet sleeve 242 is a cylindrical body provided above the thimblesleeve 241, and the coil spring 243 is interposed between the thimblesleeve 241 and the ratchet sleeve 242. A push screw is screwed onto thebase end face of the upper rod 231, and the ratchet sleeve 242 is pushedby the head flange of the push screw. At this time, the coil spring 243is sandwiched between the ratchet sleeve 242 and the thimble sleeve 241.

Between the ratchet sleeve 242 and the thimble sleeve 241, a ratchetmechanism (not shown) is provided. Here, the rotation direction of theratchet sleeve 242, the thimble sleeve 241, or the rod 230 in thedirection of feeding the rod 230 downward (in the direction ofprotruding the contact point 250) is a positive rotation direction. Incontrast, the rotation direction of the ratchet sleeve 242, the thimblesleeve 241, or the rod 230 in the direction of feeding the rod 230upward (the direction in which the contact point 250 is moved backward)is a negative rotation direction. The ratchet mechanism allows theratchet sleeve 242 to idle against the thimble sleeve 241 in thepositive rotation direction and does not allow the ratchet sleeve 242 toidle in the negative rotation direction.

When the ratchet sleeve 242 is subjected to (positive) rotary operation,the rotation of the ratchet sleeve 242 is transmitted to the rod 230 viathe coil spring 243 and the thimble sleeve 241.

There is an upper limit to the force (rotational force) transmitted fromthe ratchet sleeve 242 to the rod 230. That is, if the rod 230 isattempted to be rotated with a force exceeding the frictional force(static frictional force) acting between the ratchet sleeve 242, thecoil spring (load regulating elastic body) 243, and the thimble sleeve241, the ratchet mechanism causes the ratchet sleeve 242 to idle againstthe thimble sleeve 241. The thimble part 240 constitutes a constantpressure mechanism that regulates the upper limit of the force(measuring force) acting between an object to be measured and thecontact point 250. Conversely, a predetermined force (measuring force),which can be defined by the indentation amount of the push screw, isgenerated between the object to be measured and the contact point 250,and when the contact point 250 applies the predetermined force(measuring force) to the object to be measured, the reaction force isapplied to the contact point 250, that is, the electric inside-diametermeasuring device 200.

The lower rod 233 is provided inside the head cylinder part 215.

The upper end of the lower rod 233 is in contact with the lower end ofthe upper rod 231. The lower end of the lower rod 233 is conical.

The contact point 250 is provided in the head cylinder part 215 to moveforward and backward in a direction perpendicular to the axial directionof the rod 230.

Three contact points 250 are provided at 120° intervals in the headcylinder part 215. Each contact point 250 has a thin round shaft tip 252made of carbide at its outer end. When each contact point 250 movesforward in the protruding direction, the round shaft tip 252 is broughtinto contact with the inner wall of the object to be measured.

The inner end side of each contact point 250 is formed with a taperedsurface 251, and the tapered surface 251 is brought into contact withthe conical surface of the lower rod 233. The conical surface of thelower rod 233 and the tapered surface 251 of each contact point 250constitute a displacement direction conversion means for changing thedirection of force and displacement to a right angle.

Inside the head cylinder part 215, a spring 216 (for example, platespring) corresponding to each contact point 250 is provided, one end ofthe plate spring 216 is fixed to the inner wall of the head cylinderpart 215, and the other end of the plate spring 216 is fixed to thecontact point 250.

Each plate spring 216 biases the corresponding contact point 250 in thedirection of being accommodated in the head cylinder part 215. When therod 230 is pulled upward by an external force, the force of the platespring 216 causes the contact point 250 to follow the rod 230 and tomove in the direction of entering the head cylinder part 215.

The part of the head cylinder part 215 (the tip end part of theinside-diameter measuring device) where the contact point 250 isprotruded and accommodated is also referred to as the measuring headpart 220.

The displacement detection part 260 is provided inside the middlecylinder case part 213 to detect displacement of the upper rod 231.

The displacement detection part 260 is what is called a rotary encoderincluding a rotor 261 provided to rotate integrally with the upper rod231, a stator 262 that counts the rotation of the rotor 261, and asignal processing calculation unit (not shown). The detection method ofthe displacement detection part 260 is not particularly limited, andexamples of the displacement detection part 260 include a photoelectricencoder, a capacitive encoder, an electromagnetic induction encoder, amagnetic encoder, and the like.

The outer case part 270 is an outer cylinder part that covers theoutside of the cylinder case part 210. The outer case part 270 isprovided to cover the electric inside-diameter measuring device 200above the middle of the lower cylinder case part 214. The outer casepart 270 is constituted by two parts of an outer case body part 271 thataccommodates the middle part thereinside and an outer case upper part272 that accommodates the upper part thereinside. The outer case bodypart 271 is a cylindrical body that covers the entire middle cylindercase part 213 corresponding to the middle part of the electricinside-diameter measuring device 200, as well as the upper end side ofthe lower cylinder case part 214 and the lower end side of the uppercylinder case part 211.

The outer case upper part 272 is a cylindrical body connected to theupper end of the outer case body part 271 and covers the upper cylindercase part 211 constituting the upper part of the electricinside-diameter measuring device 200.

The display unit 273 includes a display part 274 and is attached to theside openings of the middle cylinder case part 213 and the outer casebody part 271 to close the openings. The display part 274 is the digitaldisplay part 274 (for example, a liquid crystal display panel or anorganic EL display panel) fitted into the central area of the displayunit 273. The display part 274 shows measurement values and otherinformation calculated by the signal processing calculation unit (notshown).

The display unit 273 is provided with a connector, and measurementvalues calculated by the signal processing calculation unit (not shown)are output externally.

The electric drive unit 280 is a drive unit that rotates the ratchetsleeve 242 of the thimble part 240. The electric drive unit 280 isattached above the outer case upper part 272. The electric drive unit280 is, for example, a motor, and the rotational output of the motor istransmitted to the ratchet sleeve 242 via a power transmission mechanism(a gear train, a coupling belt, a coupling shaft, a coupling link, orthe like).

The operation of the electric inside-diameter measuring device 200 isbasically the same as that of an existing manual inside-diametermeasuring device, except that the rod is fed by the electric drive unit280.

When the rod 230 is moved forward and backward by electric power, thecontact points 250 are protruded from and accommodated in the headcylinder part 215 in accordance with the movement of the lower rod 233.By detecting the displacement (position) of the rod 230 when the threecontact points 250 are in even contact with the inner wall of a hole tobe measured, the inside diameter of the hole to be measured is obtainedas a measurement value.

(Support Frame Part 300)

The support frame part 300 is an L-shaped member in side view andincludes a support column part 310 and a support base part 320. Thesupport base part 320 is attached to the lower end of the support columnpart 310 at right angles in the vertical direction.

The support column part 310 is adjacent and parallel to the electricinside-diameter measuring device 200. The restriction means 500 isprovided on the front face side of the support column part 310, and therestriction means 500 switches between holding and releasing of theelectric inside-diameter measuring device 200. This point is describedlater.

The support base part 320 is provided by being bent in an L-shape fromthe lower end of the support column part 310 toward the electricinside-diameter measuring device 200.

The support base part 320 includes a first insertion hole 321 throughwhich the head cylinder part 215 of the electric inside-diametermeasuring device 200 is inserted. The electric inside-diameter measuringdevice 200 is attached in such a manner that the upper part above thelower cylinder case part 214 is placed on the support base part 320 viathe floating joint part 400 while the head cylinder part 215 has passedthrough the first insertion hole 321.

(Floating Joint Part 400)

The floating joint part 400 is described.

FIG. 6 is an exploded view of the floating joint part 400.

FIG. 7 is a cross-sectional view of the floating joint part 400.

The floating joint part 400 is a joint (or coupling mechanism) thatallows rotation of the electric inside-diameter measuring device 200with respect to the support frame part 300 and also allows horizontaltranslation of the electric inside-diameter measuring device 200 withrespect to the support frame part 300. Even if there is an axialmisalignment (inclination and distortion) between the electricinside-diameter measuring device 200 and a hole to be measured, thefloating joint part 400 allowing rotation and translation allows theelectric inside-diameter measuring device 200 to autonomously adjust itsown position and posture.

The floating joint part 400 includes a rotation-allowing mechanism part410 and a translation-allowing mechanism part 420.

The rotation-allowing mechanism part 410 includes a first spring holder411, a spring (coil spring) 412 (flexible body or elastic body), and asecond spring holder 413. The first spring holder 411 and the secondspring holder 413 are roughly ring-shaped, with a flange extendingradially outward from the ring.

As shown in the cross-sectional view in FIG. 7 , the first spring holder411 is fitted externally to the outer surface of the lower cylinder casepart 214 at the upper side of the lower cylinder case part 214, and thefirst spring holder 411 is thereby fixedly attached to the electricinside-diameter measuring device 200. Here, the lower end face of theouter case body part 271 and the first spring holder 411 arecontinuously integrated, and the position where the first spring holder411 is attached to the electric inside-diameter measuring device 200 isfixedly regulated.

As one embodiment, the first spring holder 411 may be installed in sucha manner that the height (position) of the first spring holder 411corresponds to the height (position) of the center of gravity of theelectric inside-diameter measuring device 200. For example, the firstspring holder 411 is installed in such a manner that the height(position) of the first spring holder 411 is approximately the same asthe height (position) of the center of gravity of the electricinside-diameter measuring device 200. Alternatively, the first springholder 411 may be installed in such a manner that the height (position)of the first spring holder 411 is within 20%, 15%, 10%, or 5% (of thelength of the electric inside-diameter measuring device in the verticaldirection) above or below the height (position) of the center of gravityof the electric inside-diameter measuring device 200.

The upper end of the coil spring 412 is received by the first springholder 411 while the coil spring 412 accommodates the lower cylindercase part 214 (electric inside-diameter measuring device 200)thereinside. The lower end of the coil spring 412 is received by thesecond spring holder 413.

As one embodiment, instead of one coil spring 412, a plurality ofelastic bodies or springs may be provided to surround the electricinside-diameter measuring device 200 (at equal angular intervals).

Although it is better for the spring to have a larger diameter (for thedistance between the spring and the center axis of the electricinside-diameter measuring device to be larger) to support the electricinside-diameter measuring device, if the diameter of the spring is toolarge (the distance between the spring and the center axis of theelectric inside-diameter measuring device is too large), the measurementpressure of the inside-diameter measuring device alone cannotautonomously adjust the posture of the electric inside-diametermeasuring device to scan the axis of the hole. If the diameter of thespring is to be increased (the distance between the spring and thecenter axis of the electric inside-diameter measuring device is to beincreased), the spring constant (modulus of elasticity) should bedecreased. If the diameter of the spring is to be reduced (the distancebetween the spring and the center axis of the electric inside-diametermeasuring device is to be reduced), the spring constant (modulus ofelasticity) may be slightly increased. Although the elastic spring isdescribed in the exemplary embodiment, the member coupling the firstspring holder 411 and the second spring holder 413 may be a flexiblemember without elasticity instead of the coil spring 412, as long as theposture adjustment in the rotational direction of the electricinside-diameter measuring device can be allowed.

The second spring holder 413 is coupled to the translation-allowingmechanism part 420.

As shown in the cross-sectional view in FIG. 7 , a ring hole 414 of thesecond spring holder 413 has a slight length (height) in the axialdirection, and the diameter of the ring hole 414 is slightly larger thanthe cylinder case part 210 (lower cylinder case part 214) of theelectric inside-diameter measuring device 200 to the extent that itallows the inclination of the electric inside-diameter measuring device200. The ring hole 414 may be a tapered hole 414 where the ring holeincreases in diameter toward the upper side or lower side.

The translation-allowing mechanism part 420 includes a horizontal plate(translation body) 421 and a ball roller (bearing) 423.

The horizontal plate 421 is a plate provided above the support base part320. The horizontal plate 421 includes a second insertion hole 422through which the electric inside-diameter measuring device 200 (lowercylinder case part 214) is inserted. The second spring holder 413 isfitted into the second insertion hole 422 from above. That is, therotation-allowing mechanism part 410 is on the horizontal plate 421, andthe electric inside-diameter measuring device 200 is supported by therotation-allowing mechanism part 410. In other words, the electricinside-diameter measuring device 200 is supported on the horizontalplate 421 with the rotation-allowing mechanism part 410 interposed.

The ball roller 423 is provided on the upper face of the support basepart 320. Here, four ball rollers 423 are installed at 90-degreeintervals around the first insertion hole 321 and the second insertionhole 422, and the horizontal plate 421 is placed on the ball rollers423.

The horizontal plate 421 placed on the ball rollers 423 can movehorizontally with very little force, almost without friction. On theother hand, to deform the coil spring 412 (elastic body) as therotation-allowing mechanism part 410 requires a force to resist theelastic force. Therefore, in the present exemplary embodiment, when aforce (rotational or translational force) acts on the electricinside-diameter measuring device 200, the translation-allowing mechanismpart 420 relatively has priority in displacement.

The operation of adjusting the position and posture of the electricinside-diameter measuring device 200 by the action of the floating jointpart 400 is described with reference to FIGS. 8 to 12 .

For example, FIG. 8 shows a case assuming that a hole to be measured hasbeen machined with a deviation from the design value and that the holethat should have been drilled vertically has an inclination and isslightly deviated from the position of the design value to the right inthe drawing. The electric inside-diameter measuring unit 120 is moved tothe hole by the robot arm part 130, and the measuring head part 220 isinserted into the hole. Even if the drive control of the robot arm part130 is accurate, there is a deviation in position and angle between theaxis of the electric inside-diameter measuring device 200 and the axisof the hole to be measured, because the hole to be measured is deviatedfrom the design value.

Now, in order to accurately measure the inside diameter of a hole to bemeasured, all the three contact points 250 need be brought into evencontact with the inside wall of the hole to be measured.

First, the electric drive unit 280 drives the rod 230 to move the rod230 downward. Then, the tip (cone) of the lower rod 233 protrudes thecontact points 250, and one of the three contact points 250 closer tothe inner wall of the hole to be measured is brought into contact withthe inner wall of the hole to be measured.

As the lower rod 233 continues to protrude the contact points 250, areaction force is applied to the contact points 250 from the inside wallof the hole. This reaction force causes the electric inside-diametermeasuring device 200 to be pushed in the opposite direction. Thereaction force pushes near the lower end of the lower rod 233 from thecontact points 250, but the displacement of the horizontal plate 421occurs first before the deformation of the coil spring 412 of therotation-allowing mechanism part 410. Thus, as shown in FIGS. 9 and 10 ,the displacement of the horizontal plate 421 first absorbs the axialmisalignment between the electric inside-diameter measuring device 200and the hole to be measured.

The first insertion hole 321 of the support base part 320 has a diameterlarge enough to allow horizontal movement of the electricinside-diameter measuring device 200.

At the time of FIG. 9 (FIG. 10 ), the axal inclination is not yetaligned between the electric inside-diameter measuring device 200 andthe hole to be measured. When the lower rod 233 continues to protrudethe contact points 250 from the state shown in FIG. 9 (FIG. 10 ), thetips (round shafts) of the contact points 250 are brought into contactwith the inner wall of the hole, and at this time (because of the lengthof the three round shafts), the reaction force applied to the electricinside-diameter measuring device 200 from the inner wall of the hole tobe measured has a moment of rotation. At this time, the reaction forcefrom the inner wall of the hole deforms the coil spring 412 of therotation-allowing mechanism part 410 as shown in FIGS. 11 and 12 , andthe inclination of the electric inside-diameter measuring device 200 isadjusted to align the axis of the electric inside-diameter measuringdevice 200 with the axis of the hole to be measured. The ring hole 414of the second spring holder 413 allows the inclination of the electricinside-diameter measuring device 200.

Eventually, when the three contact points 250 push against the innerwall of the hole to be measured with the predetermined measuringpressure, the floating joint part 400 (the rotation-allowing mechanismpart 410 and the translation-allowing mechanism part 420) allows theelectric inside-diameter measuring device 200 to autonomously adjust itsown position and posture to accurately measure the inside diameter ofthe hole to be measured. In other words, once the robot arm part 130 isable to insert the measuring head part 220 of the electricinside-diameter measuring device 200 into the hole to be measured, theinside diameter of the hole can be accurately measured through automaticposture adjustment without the need for manual sensory adjustment oradvanced feedback control.

(Restriction Means 500)

The restriction means 500 is provided to the support frame part 300(support column part 310) to hold and support the electricinside-diameter measuring device 200. The restriction means 500 includestwo clamping pieces 510 that clamp the electric inside-diametermeasuring device 200 from a direction perpendicular to the axis asshown, for example, in FIGS. 2 and 3 . Here, the clamping pieces 510clamp the outer case body part 271 from both sides. The clamping pieces510 are movable, and the restriction means 500 can switch between a holdstate of the electric inside-diameter measuring device 200 and a releasestate in which the holding is released.

Even though the clamping pieces 510 are opened to release the electricinside-diameter measuring device 200, the gap between each clampingpiece 510 and the electric inside-diameter measuring device 200 ispreferably limited to a predetermined upper limit (about 5 mm or 10 mm)to regulate any large displacement (translation or inclination) of theelectric inside-diameter measuring device 200 beyond the limit.

The electric inside-diameter measuring device 200 is placed on thesupport base part 320 (support frame part 300) via the floating jointpart 400.

In order for the electric inside-diameter measuring device 200 to beable to autonomously adjust its posture according to a hole to bemeasured with its own measuring pressure, the floating joint part 900needs to be soft (softness or flexibility). Therefore, if the electricinside-diameter measuring device 200 is simply placed on the floatingjoint part 400, the electric inside-diameter measuring device 200 canswing unsteadily, be inclined greatly, or fall down, depending on therigidity (softness) of the floating joint part 400.

From a safety point of view, it is undesirable that the electricinside-diameter measuring device 200 swings or falls down. In addition,if the posture of the electric inside-diameter measuring device 200 isnot fixed, the position of the measuring head part 220 is unstable, andthe robot arm part 130 cannot be able to insert the measuring head part220 of the electric inside-diameter measuring device 200 into the holeto be measured.

For these reasons, when the electric inside-diameter measuring device200 is not inserted in a hole to be measured, the restriction means 500clamps and holds the electric inside-diameter measuring device 200.Then, when the measuring head part 220 of the electric inside-diametermeasuring device 200 is inserted in a hole to be measured, therestriction means 500 releases the electric inside-diameter measuringdevice 200 in order for the electric inside-diameter measuring device200 to be able to autonomously change and adjust its posture (to performautonomous adjustment) by the floating joint part 400.

(Collision Detection Part 600)

The collision detection part 600 detects that the electricinside-diameter measuring device 200 has collided with something with aforce greater than a predetermined force.

FIG. 13 is an exploded view of the collision detection part.

FIG. 14 is a perspective view of the collision detection part whenviewed from a slightly rear side.

The collision detection part 600 is provided between the rear side ofthe support column part 310 and the hand part 131 of the robot arm part130. Here, the collision detection part 600 detects that a large forceis applied to the electric inside-diameter measuring device 200 in thedirection of being pushed upward from below in the Z direction (verticaldirection) when the electric inside-diameter measuring device 200approaches an object (for example, a workpiece) from above the objectand collides with the workpiece. That is, the collision detectiondirection of the collision detection part 600 is almost parallel to thedirection when the electric inside-diameter measuring device 200approaches a hole to be measured.

The collision detection part 600 includes a fixed plate 601, a mountingplate 602, a linear guide 610, a biasing means 620, and a contact sensor630.

The fixed plate 601 is attached directly or indirectly to the hand part131 of the robot and is fixedly provided to the hand part 131. Here, theforce sensor part 132 is provided between the hand part 131 of the robotand the collision detection part 600. Therefore, the collision detectionpart 600 is attached to the hand part 131 of the robot arm part 130 viathe force sensor part 132.

The mounting plate 602 is attached directly or indirectly to the rearface of the support column part 310 and is fixedly provided to thesupport column part 310 (support frame part 300). The linear guide 610is provided between the fixed plate 601 and the mounting plate 602 andguides the moving direction of the mounting plate 602 with respect tothe fixed plate 601 in the vertical direction. The linear guide 610includes a groove frame body 611 having a groove in the verticaldirection and a slide body 612 that slides in the groove of the grooveframe body 611 in the vertical direction. Here, the groove frame body611 is attached to the fixed plate 601, and the slide body 612 isattached to the mounting plate 602.

The biasing means is two coil springs 620.

One end of each coil spring 620 is fastened to the fixed plate 601, andthe other end of the coil spring 620 is fastened to the mounting plate602. Each coil spring 620 constantly biases the mounting plate 602 inthe direction of pulling down the mounting plate 602 with respect to thefixed plate 601. That is, the position of the mounting plate 602 whenthe mounting plate 602 is lowered vertically downward with respect tothe fixed plate 601 by its own weight, the weight of the electricinside-diameter measuring device 200, and the force of the coil spring620 is a reference position.

The contact sensor 630 includes a contact detection block 631 providedto the fixed plate 601 and a ball plunger 632 provided to the mountingplate 602. As shown in FIG. 14 , when the mounting plate 602 is in thereference position with respect to the fixed plate 601, the ball plunger632 on the mounting plate 602 is in contact with (fitting into) thecontact detection block 631.

Here, it is assumed that, for example, the position of a hole machinedin a workpiece is deviated significantly from the design value.

In this state, when the robot arm part 130 attempts to insert theelectric inside-diameter measuring device 200 into the hole to bemeasured from above, the measuring head part 220 of the electricinside-diameter measuring device 200 hits the workpiece. The electricinside-diameter measuring device 200 (measuring head part 220) isdeviated from the hole and hits the workpiece, and the electricinside-diameter measuring device 200 (measuring head part 220) is pushedfurther into the workpiece. Then, when a force exceeding thegravitational force of the electric inside-diameter measuring device 200and the biasing force of the biasing means (coil spring 620) are appliedto the collision detection part 600, the mounting plate 602 slidesupward and the ball plunger 632 of the mounting plate 602 is removedfrom the contact detection block 631. The contact sensor 630 transmits asignal (collision detection signal) when the contact detection block 631detects the separation of the ball plunger 632 (or when the contactdetection block 631 can no longer detect the contact of the ball plunger632).

When the collision detection part 600 detects that the electricinside-diameter measuring device 200 has collided with something, thecontrol unit 140 immediately stops the operation of the robot arm part130.

(Force Sensor Part 132)

The force sensor part 132 is, for example, a 6-axis (forces in 3orthogonal axial directions and rotational forces around the axes) forcesensor. While the collision detection part 600 is specialized to detecta force pushed up from below in the vertical direction (Z-direction),the force sensor part 132 detects forces applied to the electricinside-diameter measuring device 200 in all directions.

The multi-joint robot arm part 130 is what is called a robot arm andmoves the hand part 131, which is the tip of the robot arm part 130,three-dimensionally with the vertical and horizontal rotational driveaxes. The hand part 131 of the robot arm part 130 is coupled to thesupport frame part 300 via the force sensor part 132 and the collisiondetection part 600. The force sensor part 132 detects that the electricinside-diameter measuring device 200 has collided with an object with anunexpected force exceeding a predetermined force in directions where thecollision detection part 600 does not detect collisions (that is, indirections other than the vertical direction (Z direction)). When theforce sensor part 132 detects an unexpected collision of the electricinside-diameter measuring device 200, the control unit 140 immediatelystops the operation of the robot arm part 130. This further ensuressafety.

(Control Unit 140)

FIG. 15 is a functional block diagram of the control unit 140.

The control unit 140 may be implemented by hardware or softwareincorporated into a computer (a computer terminal including a centralprocessing unit (CPU), a ROM or a RAM storing predetermined programs)that is connected to the measuring-apparatus main body 110 by wired orwireless communication.

An operation control program (measuring part program) is installed inthe computer terminal, and the measurement operation of themeasuring-apparatus main body 110 is controlled by executing theprogram. The method of supplying the program is not limited. The programmay be installed by inserting a (nonvolatile) recording medium recordingthe program directly into the computer, or a reading device that readsthe information on the recording medium may be attached externally tothe computer to install the program into the computer from the readingdevice. Alternatively, the program may be supplied to the computer via acommunication line, such as the Internet, a LAN cable, or a telephoneline, or wirelessly.

The control unit 140 includes a measurement operation control unit 150,a robot arm drive control unit 160, and a central control unit 170.

The measurement operation control unit 150 controls the measurementoperation of the electric inside-diameter measuring device 200.

The measurement operation control unit 150 includes a restrictioncontrol unit 151, a drive control unit 152, and a measurement valueacquisition unit 153.

The restriction control unit 151 controls the opening and closingoperation of the clamping pieces 510 of the restriction means 500 tocontrol the timing of holding and releasing of the electricinside-diameter measuring device 200.

The drive control unit 152 controls the drive of the electric drive unit280 to control the forward and backward movement of the rod 230, thatis, the forward and backward movement of the contact points 250.

The measurement value acquisition unit 153 acquires a measurement valueof the electric inside-diameter measuring device 200. That is, themeasurement value acquisition unit 153 receives a sensor value of thedisplacement detection part 260 to acquire the measurement value of theinside diameter of a hole to be measured from the displacement(position) of the rod 230.

The robot arm drive control unit 160 controls the operation of the robotarm part 130.

The central control unit 170 integrally controls the measurementoperation control unit 150 and the robot arm drive control unit 160.

(Operation of Controlling Automatic Inside-Diameter Measuring Apparatus100)

The following describes a series of operations in which themeasuring-apparatus main body 110 (the electric inside-diametermeasuring unit 120 and the robot arm part 130) automatically measuresthe inside diameter of a hole to be measured under the control of thecontrol unit 140.

FIG. 16 is a flowchart of the overall operation of automaticinside-diameter measurement (automatic inside-diameter measurementoperation).

A workpiece (object to be measured) having a hole (hole to be measured)is conveyed by a conveyor belt or rail in a production line and broughtto a predetermined position in front of the measuring-apparatus mainbody 110 (the electric inside-diameter measuring unit 120 and the robotarm part 130).

The automatic inside-diameter measuring apparatus 100 automaticallysequentially performs inside-diameter measurement on the insidediameters of holes that are designated (set) as objects to be measuredamong workpieces (objects to be measured) to be conveyed. The position(coordinates) of a hole to be measured among the workpieces (objects tobe measured) has been set (stored) as part of the measuring part programin the central control unit 170. Alternatively, the inside-diametermeasurement may be performed automatically sequentially while searchingfor a hole to be measured by image recognition using a separate cameraor the like.

The first exemplary embodiment assumes that a hole to be measured is ahole drilled to have an opening on the top face in the verticaldirection, and the electric inside-diameter measuring device 200 isinserted into the hole from above while maintaining a roughly verticalorientation.

The automatic inside-diameter measurement operation includes a holeinsertion step (approaching step) (ST100), a measurement step (ST200),and a hole retraction step (retraction step) (ST300).

The hole insertion step (ST100) is a step of moving the electricinside-diameter measuring unit 120 by the robot arm part 130 andinserting the measuring head part 220 of the electric inside-diametermeasuring device 200 into a hole to be measured (in other words,approaching a workpiece from above the workpiece).

FIG. 17 is a flowchart showing an operating procedure of the holeinsertion step (ST100).

In the hole insertion step (ST100), first, the destination (targetcoordinates) of the electric inside-diameter measuring device 200 by therobot arm part 130 is set to the hole to be measured (ST110).

Then, it is confirmed that the electric inside-diameter measuring device200 is restricted by the restriction means 500 (ST120).

In the present exemplary embodiment, the state in which the restrictionmeans 500 restricts (holds) the electric inside-diameter measuringdevice 200 is a default state (which may be paraphrased as a standardstate or a reference state). However, since the holding by therestriction means 500 can be released after the electric inside-diametermeasuring device 200 is maintained or replaced, the holding state needsto be confirmed. Then, when the electric inside-diameter measuringdevice 200 is not held (ST120: NO), the restriction control unit 151transmits a signal to perform a holding step (ST130) by the restrictionmeans 500. By restricting (holding) the electric inside-diametermeasuring device 200 while the robot arm part 130 moves the electricinside-diameter measuring unit 120, the robot arm part 130 can stablysafely move the electric inside-diameter measuring device 200.

The drive of the robot arm part 130 is started (ST140) to move theelectric inside-diameter measuring unit 120, and the measuring head part220 of the electric inside-diameter measuring device 200 is insertedinto the hole to be measured.

At this time, for example, if the machining position of the hole to bemeasured is deviated from the design value, the electric inside-diametermeasuring device 200 (measuring head part 220) can unexpectedly collidewith the workpiece.

In this regard, the robot arm drive control unit 160 monitors signalsfrom the collision detection part 600 and the force sensor part 132(ST150). If a collision between the electric inside-diameter measuringdevice 200 (measuring head part 200) and the workpiece is detected(ST150: YES), the drive of the robot arm part 130 is immediately stopped(emergency stop) (ST180). Thereafter, the central control unit 170 mayreport the abnormality to an operator.

When the measuring head part 220 of the electric inside-diametermeasuring device 200 is inserted into the hole to be measured andreaches the target coordinates, the drive of the robot arm part 130 istemporarily stopped (ST170).

Next, the procedure proceeds to the measurement step (ST200).

FIG. 18 is a flowchart showing an operating procedure of the measurementstep (ST200).

In the measurement step (ST200), first, the holding by the restrictionmeans 500 is released (ST211) to put the electric inside-diametermeasuring device 200 in a released state. This makes the electricinside-diameter measuring device 200 in a state of being supported bythe support frame part 300 via the floating joint part 400, allowingautonomous adjustment of the position and posture of the electricinside-diameter measuring device 200.

Then, the drive control unit 152 transmits a drive signal to drive theelectric drive unit 280.

First, a first forward movement step (ST220) is performed. The firstforward movement step (ST220) is a step of moving the contact points 250forward until the contact points 250 are brought into first contact withthe inner wall of the hole to be measured. The electric drive unit 280(for example, a motor) is driven to move the rod 230 forward (in thiscase, downward) to move the contact points 250 forward toward the innerwall of the hole. In the first forward movement step (ST220), the motoris driven at high speed to move the rod 230 and the contact points 250as fast as possible to improve measurement efficiency. (For example, ifthe rod 230 is a screw feed, the rotational speed of the rod 230 is 100rpm to 200 rpm. In terms of the speed at which the rod 230 or thecontact points 250 move, the speed may be 10 μm/s to 20 μm/s.)

As the contact points 250 move forward toward the inner wall of thehole, the contact points 250 are brought into contact with the innerwall of the hole.

Here, in the present exemplary embodiment, the number of contact points250 is three. If the axis of the electric inside-diameter measuringdevice 200 and the axis of the hole to be measured are perfectlyaligned, the three contact points 250 can be brought into contact withthe inner wall of the hole at the same time, but there is a gap betweenthe axis of the electric inside-diameter measuring device 200 and theaxis of the hole to be measured because of the driving error of therobot arm part 130 and the machining error of the workpiece. In thiscase, any one of the three contact points 250 is brought into firstcontact with the inner wall of the hole. When any one of the threecontact points 250 has been brought into contact with the inner wall ofthe hole (ST213: YES), the first forward movement step (ST212) isimmediately stopped, and the procedure proceeds to a first backwardmovement step (ST214). The fact that the contact points 250 have beenbrought into contact with the inner wall of the hole may be confirmedby, for example, calculating the motor torque from the applied current(applied voltage) of the motor to determine that (one of) the contactpoints (has) have brought into contact with the inner wall of the holewhen the torque exceeds a predetermined value.

In the first backward movement step (ST214), the rod 230 and the contactpoints 250 are moved backward slightly in the opposite direction. Thisavoids the contact points 250 from digging into the inner wall of thehole due to its momentum after the contact points 250 have been broughtinto contact with the inner wall of the hole in the first forwardmovement step (ST212).

The distance for moving the contact points 250 backward in the firstbackward movement step (ST214) is very small, for example, 0.001 mm to0.01 mm.

The speed of backward movement of the contact points 250 in the firstbackward movement step (ST214) may be as fast as possible. For example,if the rod 230 is a screw feed, the rotational speed of the rod 230 is100 rpm to 200 rpm. In terms of the speed at which the rod 230 or thecontact points 250 move, the speed may be 10 μm/s to 20 μm/s.

After the contact points 250 are moved backward slightly in the firstbackward movement step (ST214), the contact points 250 are moved forwardagain in a second forward movement step (ST215). In the second forwardmovement step (ST215), the contact points 250 are moved forward slowly(at a low speed with fine movement).

The feed speed of the contact points 250 in the second forward movementstep (ST215) is preferably slow (micromotion). For example, if the rod230 is a screw feed, the rotational speed of the rod 230 is 10 rpm to 20rpm. In terms of the speed at which the rod 230 or the contact points250 move, the speed may be 1 μm/s to 2 μm/s.

The position and inclination of the electric inside-diameter measuringdevice 200 are autonomously adjusted by the reaction force of thecontact points 250 pushing against the inner wall of the hole. Theaction of the autonomous adjustment of the position and inclination ofthe electric inside-diameter measuring device 200 by the floating jointpart 400 allowing translation and rotation is as described above.

When the three contact points 250 are in even contact with the innerwall of the hole with the predetermined measuring pressure, theautonomous adjustment of the position and inclination of the electricinside-diameter measuring device 200 is completed. When the threecontact points 250 are in contact with the inner wall of the hole withthe predetermined measuring pressure, the ratchet mechanism (constantpressure mechanism) is activated. That is, the electric drive unit 280rotates and drives the thimble part 240 (ratchet sleeve 242) until theratchet mechanism (constant pressure mechanism) is activated, whichcauses the contact points 250 to be in even contact with the inner wallof the hole with the predetermined measuring pressure.

The second forward movement step (ST215) can be rephrased as anautonomous adjustment step.

In this state, the displacement detection part 260 detects thedisplacement (position) of the rod 230. The measurement valueacquisition unit 153 acquires the inside diameter of the hole from thedisplacement (position) of the rod 230 (ST216).

After the measurement value is acquired, the contact points 250 aremoved backward in a second backward movement step (ST217) to separatethe contact points 250 from the inner wall of the hole.

After the measurement step (ST200), the electric inside-diametermeasuring device 200 is retracted from the hole to be measured in thehole retraction step (ST300).

FIG. 19 is a flowchart showing an operation procedure of the holeretraction step (ST300). In the hole retraction step (ST300), first, theelectric inside-diameter measuring device 200 is restricted (held) bythe restriction means 500 (ST320), and then the robot arm part 130 movesthe electric inside-diameter measuring unit 120 to be retracted from thehole (ST330).

This completes the measurement of the inside diameter of one hole. Untilmeasurement of all the holes to be measured is completed, ST100 to ST300are repeated (ST400).

In this manner, according to the present exemplary embodiment, theinside diameter of a hole can be automatically measured by the electricinside-diameter measuring unit (electric inside-diameter measuringdevice 200 and the robot arm part 130) without the need for a person tohold and operate the inside-diameter measuring device.

Second Exemplary Embodiment

The above first exemplary embodiment assumes that a hole to be measuredis drilled in the vertical direction.

A second exemplary embodiment describes a case in which the automaticinside-diameter measuring apparatus 100 automatically measures theinside diameter of a hole to be measured even when the hole to bemeasured is inclined from the vertical direction.

FIG. 20 is a flowchart showing an operating procedure of a measurementstep according to the second exemplary embodiment.

Since a hole to be measured is inclined with respect to the verticaldirection, in the hole insertion step (ST100) of inserting the electricinside-diameter measuring device 200 into the hole by the robot arm part130, the electric inside-diameter measuring device 200 is inserted intothe hole while being inclined to align the inclination of the hole.Then, since the electric inside-diameter measuring device 200 isinclined, if the holding of the electric inside-diameter measuringdevice 200 by the restriction means 500 is released, the electricinside-diameter measuring device 200 can be greatly displaced(translated and inclined) by the flexibility of the floating joint part400.

If the electric inside-diameter measuring device 200 is greatlydisplaced (translated and inclined), the measuring head part 220 cancollide with the inner wall of the hole. In addition, once the electricinside-diameter measuring device 200 is greatly displaced (translatedand inclined) in the direction of gravitational force, it can betime-consuming and difficult to autonomously recover from thedisplacement (translation and inclination) only by the reaction force ofthe measuring pressure.

Therefore, in the measurement step according to the second exemplaryembodiment, a first forward movement step (ST221) is performed before areleasing step (ST224). That is, after performing the first forwardmovement step (ST221) and detecting that the contact points 250 (one ofthe contact points 250) have been brought into contact with the innerwall of the hole (ST222: YES), the contact points 250 are moved slightlybackward (a first backward movement step (ST223)). The releasing step(ST224) is performed in this state.

By performing he first forward movement step (ST221) first, the contactpoints 250 are in contact with the inner wall of the hole. Since atleast one of the contact points 250 is in contact with the inner wall ofthe hole, it can be expected that the electric inside-diameter measuringdevice 200 is not greatly displaced (translated and inclined) even ifthe holding by the restriction means 500 is released. This allows theautomatic inside-diameter measurement to be properly performed even forinclined holes to be measured.

Third Exemplary Embodiment

In the second exemplary embodiment (flowchart in FIG. 20 ), thereleasing step (ST224) is performed after the first backward movementstep (ST223), but the releasing step (ST224) may be performed before thefirst backward movement (ST223).

As shown in the flowchart in FIG. 21 , when it is detected, in a firstforward movement step (ST231), that the contact points 250 have beenbrought into contact with the inner wall of a hole (ST232: YES), theforward movement of the contact points 250 is immediately stopped.

In this state, a releasing step (ST233) is performed. Then, after thecontact points 250 are once moved backward (a first backward movementstep (ST234)), the contact points 250 are moved forward again to bringthe contact points 250 into even contact with the inner wall of the holewith the predetermined measuring pressure while the autonomousadjustment of the position and posture of the electric inside-diametermeasuring device 200 is activated. In this order of operation, automaticinside-diameter measurement can still be properly performed on theinside diameter of an inclined hole to be measured, as in the secondexemplary embodiment.

Fourth Exemplary Embodiment

A fourth exemplary embodiment is described.

The basic configuration in the fourth exemplary embodiment is similar tothat in the first exemplary embodiment, but the structure of a floatingjoint part (floating joint mechanism part) 800 is characterized.

FIG. 22 is a front view of the electric inside-diameter measuring unit120 according to the fourth exemplary embodiment.

FIG. 23 is a top view (plan view) of the floating joint part 800according to the fourth exemplary embodiment.

FIG. 24 is a cross-sectional view taken along the line XXIV-XXIV in FIG.23 .

In the fourth exemplary embodiment, the electric inside-diametermeasuring device 200 is supported to be suspended from the support framepart 300 via the floating joint part 800 in a posture in which its axis(cylinder axis or rod axis) is vertical.

The support frame part 300 in the fourth exemplary embodiment is anL-shaped member in a side view, as in the first exemplary embodiment,and includes a support column part 310 and a support base part 710.

Here, the support base part 710 has an annular shape having ahorizontally-orthogonal wall to form a vertical hole (cylindrical hole).

Since the annular wall surrounds and supports the floating joint part800, the annular wall is referred to as a support ring part 720. On thelower side face of the support ring part 720, two beams 721 that arebridged in the front-rear and left-right directions and intersectcrosswise are provided. As shown in the cross-sectional view in FIG. 24, a recessed part 722 is provided at the intersection of the beams 721.

The floating joint part 800 according to the fourth exemplary embodimentincludes a coupling block 810.

The coupling block 810 is fixedly coupled to the electricinside-diameter measuring device 200, and is translated and rotatedintegrally with the electric inside-diameter measuring device 200.

The coupling block 810 is provided inside the support ring part 720 andsurrounded by the wall of the support ring part 720 on the beams 721.The coupling block 810 is square prism-shaped (cube or rectangular).From the four corners of the lower end face of the coupling block 810,four suspension rods 811 are vertically suspended, and the suspensionrods 811 are coupled to the upper end of the electric inside-diametermeasuring device 200. That is, the electric inside-diameter measuringdevice 200 is suspended from the coupling block 810 via the suspensionrods 811.

As a rotation-allowing mechanism part of the floating joint part 800, asphere 820 is provided between the coupling block 810 and the supportbase part 710.

The sphere 820 is placed in the recessed part 722 of the support basepart 710, and the coupling block 810 is placed on the top of the sphere820.

The coupling block 810 placed on the sphere 820 allows rotation of thecoupling block 810.

FIG. 25 is a perspective view when the coupling block 810 is rotated anddisplaced with respect to the support frame part 300 (support base part710).

FIG. 26 is a cross-sectional view when the coupling block 810 is rotatedand displaced with respect to the support frame part 300 (support basepart 710).

The bottom face of the coupling block 810 is provided with a platform (aring-shaped, protruding edge) to prevent the coupling block 810 fromcoming off the sphere 820. Although pins may be used instead of thesphere if they only allow rotation of the coupling block 810, it ispreferable to use the sphere 820 because it does not inhibit thetranslation of the coupling block 810.

The support ring part 720 is provided with two guide shafts 723 thatextend horizontally and intersect crosswise. The coupling block 810 isprovided with two guide holes 812 in the front-rear and left-rightdirections to receive the two crossed guide shafts 723. The guide holes812 are formed into long holes to allow the guide shafts 723 to guidethe horizontal translation of the coupling block 810.

FIG. 27 is a top view (plan view) when the coupling block 810 istranslated in the horizontal direction.

The guide holes 812 also have some width in the height direction inorder for the guide shafts 723 not to inhibit the coupling block 810from rotating.

In order to center (balance) the normal position of the coupling block810, four springs (coil springs) 724 are interposed between the couplingblock 810 and the inner wall of the support ring part 720. Here, thesprings (coil springs) 724 are disposed between the coupling block 810and the inner wall of the support ring part 720 by winding the springs(coil springs) 724 around the guide shafts 723.

Here, the guide shafts 723 and the guide holes 812 constitute atranslation-allowing mechanism part that allows translation of thecoupling block 810.

The translation-allowing mechanism part may be constituted by providingthe guide shafts to the coupling block 810 and providing the guide holesin the support ring part 720.

The restriction means 500 may directly restrict the electricinside-diameter measuring device 200 by clamping the electricinside-diameter measuring device 200 itself with the clamping pieces510, as in the first exemplary embodiment, or may indirectly restrictthe electric inside-diameter measuring device 200 by restricting thecoupling block 810, for example.

The floating joint part 800 according to the fourth exemplary embodimentalso allows translation and rotation of the electric inside-diametermeasuring device 200 with respect to the support frame part 300. Thatis, even if there is an axial misalignment (inclination and distortion)between the electric inside-diameter measuring device 200 and a hole tobe measured, the floating joint part 800 allowing the rotation andtranslation allows the electric inside-diameter measuring device 200 toautonomously adjust its own position and posture.

Compared with the floating joint part 400 according to the firstexemplary embodiment, the floating joint part 800 according to thefourth exemplary embodiment has fewer components because the couplingblock 810 is a block that combines rotation and translation.

Even if the floating joint part 800 according to the fourth exemplaryembodiment is attached to the electric inside-diameter measuring device200, the overall size increase can be suppressed. For example, since thefloating joint part 800 according to the fourth exemplary embodiment issmall in size, even if the floating joint part 800 according to thefourth exemplary embodiment is disposed above the electricinside-diameter measuring device 200, the increase in the overall sizeof the electric inside-diameter measuring unit 120 is suppressed anddoes not have an extreme effect on the variation of the center ofgravity. Therefore, by disposing the floating joint part 800 above theelectric inside-diameter measuring device 200 instead of disposing thefloating joint part on the side of the electric inside-diametermeasuring device 200, the automatic inside-diameter measuring apparatus100 according to the fourth exemplary embodiment is suitable forautomatic inside-diameter measurement for deep holes, such asmeasurement of the inside diameter near the bottom of a deep hole.

Fifth Exemplary Embodiment

A fifth exemplary embodiment is described.

The basic configuration in the fifth exemplary embodiment is similar tothat in the first exemplary embodiment, but the structure of a floatingjoint part (floating joint mechanism part) 900 is characterized.

FIG. 28 is a perspective view of the electric inside-diameter measuringunit 120 according to the fifth exemplary embodiment.

FIG. 29 is a top view (plan view) of the electric inside-diametermeasuring unit 120 according to the fifth exemplary embodiment.

In the fifth exemplary embodiment, the electric inside-diametermeasuring device 200 is supported by the support frame part 300 via thefloating joint part 900 in a posture in which its axis (the cylinderaxis or the axis of the rod 230) is vertical.

The structure of the floating joint part 900 according to the fifthexemplary embodiment is described below.

The floating joint part 900 includes a first floating coupling body 910,a second floating coupling body 920, and a third floating coupling body930.

The first floating coupling body 910 is cup-shaped and is referred to asthe first floating coupling cup 910. The electric inside-diametermeasuring device 200 is received inside the cup-shaped interior, and thefirst floating coupling cup 910 and the electric inside-diametermeasuring device 200 are fixedly coupled. The measuring head part 220corresponding to the lower cylinder case part 214 and the head cylinderpart 215 of the electric inside-diameter measuring device 200 protrudesdownward from the bottom of the first floating coupling cup 910. Thefirst floating coupling cup 910 includes a first coupling shaft 911protruding on both sides in the front-rear direction (Y-axis).

The second floating coupling body 920 is a ring-shaped member and isreferred to as the second floating coupling ring 920. The secondfloating coupling ring 920 is provided to surround the first floatingcoupling cup 910 in a direction perpendicular to the axis of theelectric inside-diameter measuring device 200. The second floatingcoupling ring 920 includes a hole provided in the front-rear direction(Y-axis direction). This hole is for bearing the first coupling shaft911 of the first floating coupling cup 910 and referred to as a firstcoupling hole 921. The first coupling hole 921 allows the first couplingshaft 911 to rotate about the axis and the first coupling shaft 911 toslide in the axial direction. That is, the electric inside-diametermeasuring device 200 and the first floating coupling cup 910 can betranslated in the front-rear direction (Y-axis direction) and be rotatedaround the Y-axis with respect to the second floating coupling ring 920.

The second floating coupling ring 920 is provided with a second couplingshaft 922 protruding on both sides in the left-right direction (X-axis).

The third floating coupling body 930 is a horizontally-parallel platemember that supports the second floating coupling ring 920 to allowtranslation and rotation of the second floating coupling ring 920, andis referred to as the third floating coupling plate 930. The thirdfloating coupling plate 930 includes a U-shaped depressed (recessed)curved part 931 to receive the electric inside-diameter measuring device200 in the horizontal direction. At the tips of the arms constitutingboth sides of the curved part 931, holes drilled in the left-rightdirection (X-axis) are provided.

Each hole is for bearings the second coupling shaft 922 of the secondfloating coupling ring 920, and is referred to as a second coupling hole932.

The second coupling hole 932 allows the second coupling shaft 922 torotate about the axis and the second coupling shaft 922 to slide in theaxial direction. That is, the electric inside-diameter measuring device200, the first floating coupling cup 910, and the second floatingcoupling ring 920 can be translated in the left-right direction (X-axisdirection) and rotated about the X-axis with respect to the thirdfloating coupling plate 930.

The third floating coupling plate 930 is coupled to the support basepart 710 of the support frame part 300.

When considering a first virtual straight line, which is a virtualextension of the first coupling shaft 911, and a second virtual straightline, which is a virtual extension of the second coupling shaft 922, theintersection of the first and second virtual lines is preferablysubstantially aligned with the center of gravity of the electricinside-diameter measuring device 200.

The floating joint part 900 according to the fourth exemplary embodimentalso allows translation and rotation of the electric inside-diametermeasuring device 200 with respect to the support frame part 300. Thatis, even if there is an axial misalignment (inclination and distortion)between the electric inside-diameter measuring device 200 and a hole tobe measured, the floating joint part 900 allowing the rotation andtranslation allows the electric inside-diameter measuring device 200 toautonomously adjust its own position and posture.

FIG. 30 is a view when the first floating coupling cup 910 is rotatedabout the X axis.

FIG. 31 is a view when the first floating coupling cup 910 is translatedin the horizontal plane.

For ease of viewing the drawings, the electric inside-diameter measuringdevice 200 is omitted in FIGS. 30 and 31 .

With the structure of the floating joint part 900 according to the fifthexemplary embodiment, it is easier to align the rotation axis andtranslation axis with the center of gravity of the electricinside-diameter measuring device 200. This makes the posture of theelectric inside-diameter measuring device 200 more stable.

As described above, according to the present invention, inside-diametermeasurement, which has been operated manually, can be automated, whichenables full automation of the inside-diameter measurement. Automaticin-line measurement of hole diameters can be introduced in machiningfactories or the like, and is expected to significantly improveproduction efficiency.

Sixth Exemplary Embodiment

A sixth exemplary embodiment is described.

FIG. 32 is a side view of the overall appearance according to the sixthexemplary embodiment.

FIG. 33 is an enlarged cross-sectional view of a floating joint partaccording to the sixth exemplary embodiment.

The basic configuration in the sixth exemplary embodiment is similar tothat in the first exemplary embodiment, but a floating joint part 400 isdisposed above the electric inside-diameter measuring device 200 in thesixth exemplary embodiment. That is, the electric inside-diametermeasuring device 200 is supported to be suspended from the support framepart 300 via the floating joint part 400. The configuration issubstantially the same as that in the first exemplary embodiment, exceptthat almost the entire electric inside-diameter measuring device 200 isbelow the support frame part 300 and is suspended and supported from thesupport frame part 300. In the sixth exemplary embodiment (FIGS. 32 and33 ), the same reference signs are assigned to the elementscorresponding to the first exemplary embodiment.

In FIGS. 32 and 33 , a suspension rod 430 that suspends the electricinside-diameter measuring device 200 extends toward the top of theelectric inside-diameter measuring device 200. The suspension rod 430 ison the central axis of the electric inside-diameter measuring device200, and the suspension rod 430 is fixedly coupled to the electricinside-diameter measuring device 200. (The electric inside-diametermeasuring device (electric inside-diameter measuring part) 200 may beinterpreted to include the suspension rod 430.) The suspension rod 430passes through the first insertion hole 321 of the support base part320, and the first spring holder 411 is coupled to the upper end of thesuspension rod 430. The floating joint part 400 is constituted betweenthe first spring holder 411 and the support base part 320. That is, thefloating joint part 400 is roughly constituted by a ball roller 423provided in the support base part 320, a horizontal plate (translationbody) 421 provided to be translated by the ball roller 423, the secondspring holder 413 provided in the second insertion hole 422 of thehorizontal plate (translation body) 421, and the coil spring 412disposed between the first spring holder 411 and the second springholder 413.

Similarly to the first exemplary embodiment, the sixth exemplaryembodiment with this configuration and arrangement enables the operationof autonomously adjusting the position and posture of the electricinside-diameter measuring device 200 by the action of the floating jointpart 400. In addition, according to the sixth exemplary embodiment, thefloating joint part 400 is disposed above the electric inside-diametermeasuring device 200, which make it suitable for automaticinside-diameter measurement for deep holes, such as measurement of theinside diameter near the bottom of a deep hole.

The present invention is not limited to the above exemplary embodiments,and can be appropriately modified without departing from the gist.

In the description of the above exemplary embodiments, when the rod 230is driven, in addition to screw feeding by rotation, a linear motion maybe used to pull the rod 230 up and down.

In the above exemplary embodiments, a multi-joint robot arm is describedas an example of a moving means, but the moving means does not need tobe a large-scale device, but may be a one-dimensional driving apparatuswith an up-and-down elevation mechanism. For example, theone-dimensional driving apparatus includes a column, a slider thatslides along the column, a motor that drives the slider, and a powertransmission mechanism (a ball screw, a belt pulley, or the like) thatcouples the motor and the slider.

In the above exemplary embodiments, what is called a hole test(Borematic (registered trademark)) is described as an example of thestructure of the tip of the inside-diameter measuring part, but anyinside-diameter measuring device with the contact point 250 that movesforward and backward in conjunction with the rod 230 to be brought intocontact with the inside wall is applicable. For example, in the case ofthe head of a cylinder gauge, the head includes one contact point 250that moves forward and backward, an anvil that is coaxially opposed tothe contact point 250 for centering, and guide heads on both sides inthe orthogonal direction.

In the above exemplary embodiments, an inside-diameter measuring device(inside-diameter measuring part) is described as an example of ameasuring device (measuring part). However, instead of aninside-diameter measuring device (inside-diameter measuring part), acontact-type measuring device (measuring part) that measures thedimensions (inside and outside dimensions) of a workpiece (object to bemeasured) may be used.

If a measuring device (measuring part) is provided with a movableelement (which is variously called as a contact point, a measuring jaw,a spindle, or the like) that is displaceable with respect to a fixedelement and measures the dimensions of a workpiece by bringing thecontact point into contact with the workpiece or by clamping theworkpiece with the contact point, such a measuring device is applicableto the above exemplary embodiment. The measuring device (measuring part)can autonomously adjust its position or posture by the floating jointpart (floating joint mechanism part) using the reaction force applied tothe contact point from the workpiece when the contact point is incontact with the workpiece with a predetermined measuring pressure, orwhen the contact point clamps the workpiece with a predeterminedmeasuring pressure. (Therefore, the direction in which thetranslation-allowing mechanism part allows translation of an object tobe supported (measuring device) is approximately parallel to thedirection in which the contact point is brought into contact with theworkpiece (or approximately parallel to the direction of the reactionforce applied to the measuring device from the workpiece).) Examples ofthe measuring device (measuring part) include calipers, micrometerheads, micrometers, digital dial gauges (indicators), test indicators(lever-type dial gauges), and the like.

In the first, fourth, and fifth exemplary embodiments, different typesof floating joint parts 400, 800, and 900 have been described,respectively. They may be used individually or in combination.

For example, the floating joint part 400 according to the firstexemplary embodiment may be installed on the side of the electricinside-diameter measuring device 200, and the floating joint part 800according to the fourth exemplary embodiment may be further installedabove the electric inside-diameter measuring device 200.

Similarly, for example, the floating joint part 900 according to thefifth exemplary embodiment may be installed on the side of the electricinside-diameter measuring device 200, and the floating joint part 800according to the fourth exemplary embodiment may be further installedabove the electric inside-diameter measuring device 200.

Because of the length of an inside-diameter measuring device, if theinside-diameter measuring device is supported by a flexible joint, theinside-diameter measuring device sways unsteadily, inclines greatly, orslides back and forth or left and right, and is difficult to stabilize.

On the other hand, if the rigidity of the joint is increased, autonomousposition and posture adjustment cannot be performed only with weakmeasuring pressure, which needs to introduce advanced feedback control,and the like. However, this requires the introduction of an expensivesystem and a long time for position and posture adjustment. Therefore,by coupling and supporting the inside-diameter measuring device at twopoints of the side and the top of the inside-diameter measuring devicewith appropriate floating joint parts, it is expected that stability canbe achieved while flexibility of the joints can be maintained.

The above exemplary embodiments assume that the electric inside-diametermeasuring device is inserted into a hole from the top of the hole whilea nearly vertical posture is maintained, but the electricinside-diameter measuring device may be used in a horizontal posture aswell as the vertical posture, or it may approach a workpiece (hole to bemeasured) from below to top in an upside-down vertical posture.

-   -   100 Automatic inside-diameter measuring apparatus    -   110 Measuring-apparatus main body    -   120 Electric inside-diameter measuring unit    -   200 Electric inside-diameter measuring device    -   210 Cylinder case part    -   211 Upper cylinder case part    -   212 Female thread    -   213 Middle cylinder case part    -   214 Lower cylinder case part    -   215 Head cylinder part    -   216 Plate spring    -   220 Measuring head part    -   230 Rod    -   231 upper rod    -   232 Feed screw    -   233 Lower rod    -   240 Thimble part    -   241 Thimble sleeve    -   242 Ratchet sleeve    -   243 Coil spring (load regulation elasticity)    -   250 Contact point    -   251 Tapered surface    -   252 Round shaft tip    -   260 Displacement detection part    -   261 Rotor    -   262 Stator    -   270 Outer case part    -   271 Outer case body part    -   272 Outer case upper part    -   273 Display unit    -   274 Display part    -   280 Electric drive unit    -   300 Support frame part    -   310 Support column part    -   320 Support base part    -   321 First insertion hole    -   400 Floating joint part (floating joint mechanism part)    -   410 Rotation-allowing mechanism part    -   411 First spring holder    -   412 Coil spring    -   413 Second spring holder    -   414 Ring hole    -   420 Translation-allowing mechanism part    -   421 Horizontal plate    -   422 Second insertion hole    -   423 Ball roller    -   430 Suspension rod    -   500 Restriction means    -   510 Clamping piece    -   600 Collision detection part    -   601 Fixed plate    -   602 Mounting plate    -   610 Linear guide    -   611 Groove frame    -   612 Slide body    -   620 Coil spring    -   630 Contact sensor    -   631 Contact detection block    -   632 Ball plunger    -   132 Force sensor part    -   130 Multi-joint robot arm part (robot arm part)    -   131 Hand part    -   140 Control unit    -   150 Measurement operation control unit    -   151 Restriction control unit    -   152 Drive control unit    -   153 Measurement value acquisition unit    -   160 Robot arm drive control unit    -   170 Central control unit    -   710 Support base part    -   720 Support ring part    -   721 Beam    -   722 Recessed part    -   723 Guide shaft    -   724 Spring (coil spring)    -   800 Floating joint part (floating joint mechanism part)    -   810 Coupling block    -   811 Suspension rod    -   812 Guide hole    -   820 Sphere    -   900 Floating joint part (floating joint mechanism part)    -   910 First floating coupling cup (first floating coupling body)    -   911 First coupling shaft    -   920 Second floating coupling ring (second floating coupling        body)    -   921 First coupling hole    -   922 Second coupling shaft    -   930 Third floating coupling plate (third floating coupling body)    -   931 Curved part    -   932 Second coupling hole

1. A control method of an automatic inside-diameter measuring apparatus,the automatic inside-diameter measuring apparatus comprising: aninside-diameter measuring part including a contact point configured tomove forward and backward in a direction perpendicular to a cylinderaxis of a cylinder case part, an electric drive unit configured to movethe contact point forward and backward, and a displacement detectionpart configured to detect displacement of the contact point; a movingmeans for relatively moving the inside-diameter measuring part withrespect to an object to be measured to insert and retract theinside-diameter measuring part into and from a hole to be measured; anda control unit configured to control operation of the inside-diametermeasuring part and the moving means, the control method comprising: ahole insertion step of inserting, by the moving means, theinside-diameter measuring part into the hole to be measured; ameasurement step of bringing the contact point into contact with aninner wall of the hole to measure an inside diameter of the hole; and ahole retraction step of retracting the inside-diameter measuring partfrom the hole by the moving means.
 2. The control method of an automaticinside-diameter measuring apparatus according to claim 1, wherein theautomatic inside-diameter measuring apparatus further includes: asupport frame part configured to support the inside-diameter measuringpart and to couple the inside-diameter measuring part to the movingmeans; and a floating joint part interposed between the support framepart and the inside-diameter measuring part to allow relativetranslation and rotation of the inside-diameter measuring part withrespect to the support frame part the hole insertion step includingtemporarily stopping drive of the moving means after the inside-diametermeasuring part is inserted by the moving means into the hole to bemeasured, and the measurement step includes an autonomous adjustmentstep of autonomously adjusting, by the inside-diameter measuring part, aposition and posture of the inside-diameter measuring part itself toalign the cylinder axis of the cylinder case part with an axis of thehole to be measured while the inside-diameter measuring part isrelatively displaced with respect to the support frame part by areaction force applied to the inside-diameter measuring part from theinner wall of the hole to be measured when the electric drive unit movesthe contact point forward and brings the contact point into contact withthe inner wall of the hole to be measured.
 3. The control method of anautomatic inside-diameter measuring apparatus according to claim 2,wherein the automatic inside-diameter measuring apparatus furtherincludes a restriction means for clamping the inside-diameter measuringpart from a direction intersecting the cylinder axis the restrictionmeans is configured to switch between a holding state and a releasestate of the inside-diameter measuring part by performing a holding stepof clamping and restricting the inside-diameter measuring part and arelease step of releasing the restriction of the inside-diametermeasuring part the restriction means maintains the holding state of theinside-diameter measuring part during the hole insertion step and thehole retraction step, and the measurement step includes performing, bythe restriction means, the releasing step before the autonomousadjustment step to release the restriction of the inside-diametermeasuring part.
 4. The control method of an automatic inside-diametermeasuring apparatus according to claim 3, wherein the control unitincludes a drive control unit configured to control the electric driveunit the measurement step includes: a first forward movement step ofmoving, by the drive control unit, the contact point forward until thecontact point is brought into first contact with the inner wall of thehole to be measured; a backward movement step of moving, by the drivecontrol unit, the contact point backward slightly in an oppositedirection after the first forward movement step; and a second forwardmovement step of moving, by the drive control unit, the contact pointforward again after the backward movement step to perform the autonomousadjustment step.
 5. The control method of an automatic inside-diametermeasuring apparatus according to claim 4, wherein the releasing step isperformed before the first forward movement step.
 6. The control methodof an automatic inside-diameter measuring apparatus according to claim4, wherein the releasing step is performed after the first forwardmovement step.
 7. The control method of an automatic inside-diametermeasuring apparatus according to claim 4, wherein a constant pressuremechanism configured to regulate an upper limit of the reaction forceapplied to the contact point from the inner wall of the hole to bemeasured is provided in a force transmission path from the electricdrive unit to the contact point, and the drive control unit terminatesthe second forward movement step when the constant pressure mechanism isactivated.
 8. The control method of an automatic inside-diametermeasuring apparatus according to claim 1, wherein the automaticinside-diameter measuring apparatus further includes a collisiondetection part configured to detect that the inside-diameter measuringpart has collided with an object, and the hole insertion step is stoppedwhen the collision detection part detects a collision.
 9. A controlmethod of an automatic measuring apparatus, the automatic measuringapparatus comprising: a measuring part including a contact pointprovided to move forward and backward with respect to a fixed element,an electric drive unit configured to move the contact point forward andbackward, and a displacement detection part configured to detectdisplacement of the contact point; a moving means for relatively movingthe measuring part with respect to an object to be measured to bring themeasuring part closer to or in contact with the object to be measured;and a control unit configured to control operation of the measuring partand the moving means, the control method includes: an approaching stepof bringing, by the moving means, the measuring part closer to theobject to be measured; a measurement step of bringing the contact pointinto contact with the object to be measured to measure a dimension ofthe object to be measured; and a retraction step of retracting, by themoving means, the measuring part from the object to be measured.
 10. Thecontrol method of the automatic measuring apparatus according to claim9, wherein the automatic measuring apparatus further includes: a supportframe part configured to support the measuring part and to couple themeasuring part to the moving means; and a floating joint part interposedbetween the support frame part and the measuring part to allow relativetranslation and rotation of the measuring part with respect to thesupport frame part the approaching step including temporarily stoppingdrive of the moving means after the measuring part is brought, by themoving means, closer to or into contact with the object to be measured,and the measurement step includes an autonomous adjustment step ofautonomously adjusting, by the measuring part, a position and posture ofthe measuring part itself while the measuring part is relativelydisplaced with respect to the support frame part by a reaction forceapplied to the measuring part from object to be measured when theelectric drive unit moves the contact point forward and brings thecontact point into contact with object to be measured.